Passengers will experience at least five minutes of weightlessness before they make their way back down to Earth.

Commercially viable

XCOR's Lynx vehicle will carry only one passenger in addition to the pilot.

But one thing both projects have in common is that they hope to be flying at least four times a day, making space travel a much more commercially viable project for small start-ups.

Mr Greason says advances in technology and engineering have helped the boom in private space companies.

Of particular significance is a carbon composite material that he describes as a "very hi-tech form of papier mache".

The composite is being used in commercial airlines to build Boeing's Dreamliner.

Small teams are able to develop vehicles using the material, which brings their production costs down.

So what does the growth of private space companies mean for Nasa?

Like other federal agencies, it is subject to budgetary restraints as President Barack Obama tries to get the economy back on track.

Nasa is due to keep its $19bn budget, but will be spending at least $270m to fund four commercial companies - including serial entrepreneur Elon Musk's SpaceX - to build a Commercial Crew Vehicle capable of taking US astronauts to the International Space Station.

However, this is not expected to happen until at least 2016.

Meanwhile US astronauts will be paying customers of the Russian space agency once the final shuttle launch of Atlantis completes its mission at the end of June, marking the end of a 30-year programme.

For more than 50 years, Nasa has been, and will remain, the main customer for spaceflight and exploration.

Although it has been working for many years with private companies such as Lockheed and Boeing, this has been on a "fixed costs plus" basis meaning that funding was really open-ended and therefore expensive in order to get the job done.

Innovation

All eyes are on Mojave as the age of commercial space travel dawns

Ed Mango is director of the Nasa Space Transportation Office, and oversees the commercial companies building these new commercial crew vehicles.

He says the main difference is that in the past Nasa laid all the funding on the table and owned the vehicle once it was built.

But now both Nasa and the commercial company advance funding together to develop the system, but the private company will own the hardware and Nasa will buy the service.

In anticipation of this, Mango's office has rewritten Nasa's specification documentation, cutting it by 90%. The specification still emphasises safety to a high level, but it will be up to the companies to decide how to achieve this within budget.

Mango believes there are three main reasons for the changes.

"Financially, it could be more attractive to the government, to the taxpayers," he says.

"Secondly, it helps create innovation when we don't own the system, when the companies own the system they are going to do what they think is best to be as innovative as possible.

“Start Quote

If President Obama, or whoever came in, says we're gonna get to Mars by 2040 then we ought to stick by that as a country and not worry who the President is”

End QuoteMichael LeinbachShuttle launch director

"And thirdly, it allows Nasa to concentrate on exploration and not to spend all our budget on low-Earth orbit like we do with the shuttle today."

Many of the contractors currently working on the space shuttle programme are due to lose their jobs. According to shuttle launch director Michael Leinbach, only 5% are currently being re-employed in the new ventures.

He fears the organisation may lose much of its expertise as the proposed next big Nasa project, Constellation, has been cancelled.

'Back that vision'

Michael Leinbach sympathises with President Obama's current economic predicament, but argues that Nasa needs a mission statement from the White House which successive administrations will stick to and - more importantly - fund.

"If President Obama, or whoever came in, says we're going to get to Mars by 2040 then we ought to stick by that as a country and not worry who the President is. The next President ought to back that vision and stick to it," he said.

In his office overlooking the Visitors' Space Park at Kennedy Space Centre, Frank Di Bello is positive about the changes. He is the president of Space Florida, the state agency for developing aerospace.

Find out more

Of the $270bn generated globally by the space industry, only 1% is from the launch function and he thinks that "the future belongs to commercial companies that are agile and fast on their feet".

"Many of tomorrow's successful companies don't even exist today. We need to be agile in finding them and to have them grow right here in Florida," he says.

Back at the Mojave Air and Spaceport, XCOR's Jeff Greason, who sat on the Augustine Commission to report on the future of Nasa, firmly believes that there is still a role for the organisation to do the kind of exploration that private companies cannot do.

"Space holds the future for humanity. The frontier is out there; it's waiting for us.

"Nasa can be a powerful change agent in opening that frontier if they choose to be and if Congress allows them to be."

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